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August 1987

Mapping X-linked Ophthalmic DiseasesIII. Provisional Assignment of the Locus for Blue Cone Monochromacy to Xq28

Author Affiliations

From the Center for Retinal Diseases and Ocular Genetics (Dr Lewis); Retinitis Pigmentosa Center (Dr Lewis); Departments of Ophthalmology (Dr Lewis), Pediatrics (Dr Lewis), and Medicine (Drs Lewis and Hejtmancik); Institute for Molecular Genetics (Drs Lewis and Hejtmancik and Mr Holcomb); and Howard Hughes Medical Institute (Dr Hejtmancik and Mr Holcomb), Baylor College of Medicine, Houston; and the Center for Human Genetics, Bar Harbor, Me (Drs Bromley, Wilson, and Roderick). Dr Lewis is the Olga Keith Weiss Scholar, 1986-1987, of Research to Prevent Blindness Inc, New York.

Arch Ophthalmol. 1987;105(8):1055-1059. doi:10.1001/archopht.1987.01060080057028

• Blue cone monochromacy (BCM) is an infrequent X-linked retinal disorder typified by poor central visual acuity and color discrimination, early onset of nystagmus, variable degrees of myopia and astigmatism, and a nearly normal retinal appearance. The physiologic functions of rods and blue cones are preserved. The regional location of the genetic mutation causing BCM has been unknown. We have applied the modern molecular techniques of analysis of restriction fragment length polymorphisms to three multigenerational kindreds in which BCM is segregating. Significant linkage is established to two DNA markers, DXS15 and DXS52, each of which maps to the vicinity of Xq28. Regional localization of the locus for BCM has the potential to improve carrier detection and to provide antenatal diagnosis in families at risk for the disease.